In 1965, NEC completed the NEAC-32 high-capacity magnetic disk memory unit for the FONTAC computer of the Japan Electronic Computer Technology Research Consortium.
This unit reduced access time by providing 16 movable heads, held at a fixed spacing, for each disk side. The magnetic heads used a flying system and had a float distance of 7μm. Since the system had multiple disks and magnetic heads, and used the flying system, it was difficult to synchronize using a timing track, and an FM modulation system was adopted to enable self-synchronization using information signals.
|Total memory capacity(bit)||270,336,000|
|Latency time(msec)||Average 17|
|Number of disks(for data)||25|
|Number of recording sides(for data)||48|
|Number of tracks(per side)||Inner zone 128+Outer zone 128|
|Number of magnetic heads(per side)||Inner zone 8+Outer zone 8|
|Recording density(bit/mm)||Max. 17|
|Rotation speed(rpm AC60Hz)||1,800|
|Data transfer speed||Inner zone||510kbit/s|
|Weight (kg)||Approx. 1000|